A method for adjusting a printing head usage amount of a 3D printer and a control device are provided. The method is adapted to control the control device of the 3D printer. The method includes following steps. At least one printing head of the 3D printer is divided into a plurality of sections. An accumulated printing point number of each of the sections is obtained. At least one specific section used for printing a 3D object is selected from the sections according to the accumulated printing point number of each of the sections. The method for adjusting the printing head usage amount of the 3D printer and the control device can avoid excessively high usage amount of some nozzles.